Line-joint tester.



H. H. SIMPSON.

LIKE JOINT TESTER.

Arruonml nun our. u. mo.

Patnuted Nov. 7, 1011.

.nf M/.a a. mf

l is a specification.

HENRY HARRISON SIMPSON, OF PILOT GROVE. MISSOURI.

LINE-JOINT TESTER.

Specication ot' Letters Patent.

Patented Nov. 7, 1911.

Application Med Dctober 24, 1910. Berta! lo. 588.622.

To all whom il may com-ern:

Be it known that I, HENRY llaiuusois' Sixreox, a citizen of the United States of America, and a 'resident of lilot (ii-ove, Cooper county, and State of Missouri, have invented a new and useful Improvement in Line-Joint Testers,

-My invention pertains to testing apparatus and relates articu arly to that class of apparatus emp oyed `in ascertaining the e ectrical conductivity; of telephone and telel gralgkh lines and the `ke. j

' e principal object of my invention is ,f to provide a novel and improved line tester 1 by means of which the condition of the line or lines with respect to a standard normal i condition of conductivitv may be readily determined without involving any calculations or necessitating the determination iii any unit of the electrical properties of the line under test.

In the design of a transmission line` whether for the electrical transmission of intelligence or for the transmission of power, a size of conductor is selected that meets the design conditions and allows of the transmission of the required amount of current with a predetermined allowable voltage drop. However, as it is impossible to obtain and erectsingle lengths of conductors between two relatively distant points, it is necessary to employ a number of relatively short lengths which are bonded together to form a continuous line. 'lhesc bonds arc in a majority of cases made by simplv twisting the ends of the two adjacent lengths of conductor together. 'lhc're is thus introduced into the line a series of 'oints that, when the line is new and the joints are well made, do not materially iiicrease the resistance of the line as a whole, as there is a good electrical contact between the two conductors at the joint. However, the action of the elements results in coating the conductors at the 'oint with an oxid of lthe metal of which tie conductor is composed, and this greatly lcssens the conductivity of the joint as compared to the continuous conductor. Especially is this truc in a. joint that is not tightly made, a. the surface of the conductors composing the joint are not pressed upon each other with of which the following l a minimum air space therebetween. lt will he readily observed that the cumulative "eflect of a number of these loose and corroded joints in a line will result in a positive detriment tothe transmission. Resistance measurements of such a line may be made, but beyond determining thc fact that the section of line under test. shows u total resistance in ohms above that normally to be expected from the size, character of the wire and insulation of the line, no accurate location can be made of the cause producing this cll'cct.

In my inventionl I provide a suitable testing device of great simplicity by means of which the electrical conductivity of a joint or bo'id in the line may be accurately and quickly determined, thereby providing a means whereby the cause producing an undesirable ell'ect in the line 'as a-\\'li0le muy be accurately located for its subsequent rcmoval.

In the figures which accompany and form a. part of this specification Figure 1 illustrates in diagram my device applied to use on a line with ground return; Fig. 2 illustrates diagraiumatically my device applied to use on a metallic circuittclephonc line; Fig. 3 is a view partially in section of my coniplete device; Fig. 4 illustrates partially in section one of the contact hooks of my device.

Referring to Figs. 1 and 2, in which like numerals designate corresponding parts throughout, I have illustrated diagrammatically tlie method of applying my device to the testing of joints in both a grounded and metallic transmission line.

In Fig. l, a line wire connects two telephone stationsQO and 21, the circuits bein completed through thc earth, as indicate A grounded line, such as that indicated in the figure, carries not only the currents couveying speech, but it also carries foreign or earth currents and these, as is well known in the art, canse the line to bome noisy. Especially is this true Where the line is in the neighborhood of alternating current power distributing lines or plants. Therefore, if a telephone receiver 1 of the usual resistance be bridged b the wires 3 and 4 across a joint 2 in the tine 5, o divided circuit will be formed, and if the joint 2 is of substantially equal resistance to a corresponding length of thc line wire, the resistance of the line bctwecn'the connections of the terminals of thereceiver l wil! he tis suh-tantially zero, ns the length of the line. intlltlling the joint hetween stu-h eonneetion is eomlmrutivelv .s tort. 'there will., therefore. be no dit ereure of potential hetween the eonneetion ot the wire Il with the` line and the eonueetion of the wire 'l with the ijne 5, and hen' uo enrrent will'tlow thmueh the reeeiver l. 'l'here will, theretore. e evideneed no line noise in the reeeiver, and the joint '2 may he eonsidered to he .substantially perfeet with respect to its eondlutivit'v. It will he ohserved from the foregoing that as a joint loosem: and eorrodes and so introdnees more resistanee into the line. the "oltage drop aeross the terminals of the reeeirer I will inet-ease and the line noise will he more and more notieeahle in the receiver as'more and more enrrent is flowing therethrough. We have. therefore, a war of aeeuratelv determiningr the eondition ofeolulnetirity of the joints in a line whieh allows of any partieular joint being;r tested and repaired. tothe latternient of the line as a whole. .\n all nlelallie line does not letal itself to this forni ol test. un lesrethe line is grounded. 'l'he fronndinLr 0f olle Side 0f tl metztllie line t-aHses it t'v heroine unhalaneed in that it .is vl'oreed io earr enrrents from earth as well a euri-entr. eonveying speeeh. l'n my derive l therefore provide a ground eoudnetor t' t'l-`ig. 1).). whieh is attaehed to the wire under test 2.3.

provide a awiteh 7 in the ground eonneetion 6 by means of whieh the around may' he only momentarily plaeed on the line while the aetual test is taking plaee. in order that the transmission of the luie may not he pre- 'udieially atl'eeted Al'or any eonsderahle ength of time. 'lhe reeeiver l is bridged arrosti the joint 2li. as in the ease nl the grounded line just deserihml. and the operation niul result of the test are sinlilor to that just deserihed.

In ltig. 3, whieh illustrates onel eluhodituent. ol' luy deviee. a hollow handle l0 is made in seetions to t'aeilitate its transportation. A hollowtrident .shaped luemher l'l is provided with un external aerow thread upon its thunk portleln whit-h yngngea an internal .sei-ew thread in one extremity of one of the seetions of the handle t0. llaeh of the three prongs of the lnetnher 11 is internally serew threaded to admitl the externally serew threaded plugs 12. 14 and 15. .lheso plugs are made of any instituting material. sneh as hard liher or ruhher. and are. provided with ventral axial apertures whieh admi: me .shauks of thel oontuet hooks 16, 17 and 18. lespectively. A nut. 18" (Fig. 4l engages the threaded portion of tho .shank et in eontuet hook und serves-t o hold it rig-hib in the inailating.r plugr as 15. 'Iho eontaet i luiolts. one ol'I whieh is shown in Fig. It. are provided with a still' leaf spring 18'. whieh l is riveted to the I'ree evtreiuity of the hotly t portion ot' the hook 18, as indicated. Ono eonduetor :l of the head telephone 1l is insulated and extends through the hollow handle l" and through one prong of thc member ll and is .soldered to the contact hook lt. while the other insulated conductor -l is carried u) through the handle and through the mit dle prong of the member l1 and in .soldered to the hook 17. These insulated eomluetors` :t and -t emerge through a lateral openingr from the hollow portion ot' the sei-tion of the handle 10, to which is altaehed the lneniher ll and are of snllicient length to allow the head telephone 1 to be worn hy the operator vwhen the hooks lt. 17 and 1S are plaeed in eontaet with a lint.` wire :25. 'I`he insulated eondnetor i" extends u through the hollow' handle 10 and througli the remaining prong of themeniher 11 and is .soldered to llooh IS. 'l'lle other extt'tlnly ol' eondnetor ti is soldered to a metallic disk l0 whieh is rigidly attaehed to the threaded extremity of the upper section of the handle It). eorrespolnling disk 10" is attaehed to the hottoni of the threaded opening in the lower seetion of the handle It". and an insulated eonduetor tl is soldered thereto and extends in the hollow, portion olthtI handle lll toone nu-lnher oftheswiteh T. 'l'he other nieuiher ofthe switeh 'i' is ronneen-l he meansl ot the insulated eonduetor t? lo a -e'round spike R. ltl will he ohserved that the handle lll may lie extended to any ue-ired length h v the addition ot' .seetions la-tween the two illustrated: th'l requiretnents lveing that eaeh seet ion he provided with an insulated eonduetorexte|ulingthere through and eonneeted ai eaeh extremity ot the seetion with eontaets as 10' and l0". and that the set-tions shall he externally serew-threaded upon one end and internally serew-threaded upon the opposite end.

ln the praetieal applieation of|n deviee. the handle is huilt up hy sei-owing together the "arions :seetiops neeessauv to ohtain the required length of handle to allow the opg erator. while .standing on the ground. to plaee the hooks 16. t7 and IR in eontaet with the line to he tested. 'lhe head telephone l is adjusted to the operator's ear and the'hoolts 16. 17 und 19 are plaeed over the eonduetor 2.1 to inelude the loint under testi t. het ween the hoolcs t6 and 1.7., 'l`he operator then pulls down on the handle. thereby rousing the eondnetor 2.1 to ho `rripped hy eaeh hook as `shown at 15. Fig. -t. 'lhe head telephone l is in thisinanner hridged aeross the joint t. and should the line under test he u sounded line. sueh as that illustrated in Fig. 1. a eonelnsion eau readily he drawn as to whether the ioint is relatvelv lL'ood or had l.\l lot-anl ot' the sounds in the hradtelephone. as prerioud'v lest-ritual. llowever. should the line under test he a utetallie lille as that indieated in Fie'. the operator llt) thru-.t.-, the "round pike R into the enrth und elonea tte `-uiteh i', Iherehy plm-ing u ground upon the line under te.-t through eouduetor o. nwileh eondnetor tt', eonduetor 6" uml hook IH. 'l`hi.-t euuses the line to heeome noisy. during u'hieh tinte u test ol' the joint muy he mode hy menus of the reeeirer l. us hus previously heen deserilu-d.

'hile l hure illuutlnted ulnl de.-erihed one t'orm m' emlunlinwnt of my deviee. it is to he understmnl thut numerous ehnuges in the detuiloy thermf untr he nnule without depurting from the spirit of my invention.

llnving` thus deserihed n| invent ion. u'hut l ehtim un neu' und desire to .wi-ure In' lnited Stuten Letters lnteut is us lollou's:

l. In un urtiele of the elnss deserilwd. u huudle. u plurnlity of eontuets eurried upon one extremity of suid huudle. u telephone reeeiver eonneeted to u pnir of suid eontnets. nml u ground eonneetion eonneeted to nnother of l#uid eontnets for the purpose herein deserihed.

L'. lu un urtiele of the eluss deserilved. u luunlle u pluruliqv 'ot' eontuet hook enrried n mn one extremity of .-nid lnunlle` n teleilione reeeiver eonneeted to n pnr of -nid took-s. u 'round eonneetion ronueeted to uuother o #uid hooks und u Hwiteh iu uuid ground eonueetion, for the purpose herein deserlwd;

3. ln nn eleetrieol line joint tester, nu extensible huudle. u plurulity of eontuet hooks inwuluted from tueh other uml enl'l'ied upon ene extremity ol' said huudle. u telephone l'eeeiver renueeted to n puit' ol' snid hooks.

uml n ground eonueetton eonneeted to mother ol' Huid hooltfs, for u t|e.--ri'wd. i

l. ln un eleetrieul line joint tester, u hollou' exteuihlu huudle. u hollow trident. hnped memher enrried upon ont.l exltrelnity of -uid huudle. u eontuet hook enrried by eueh prong ol' .-:tid trideut l-hnped lnetnher und |u.-n|nted therefrom. n telephone rereirer eonneeted to n puir of suul eout-tet houle. uml n ground eonueetion eonueeted to the remuining one ot'v unid ,eontuet hooks, tor llu` pm'poe herein deserlwd.

.'n. ln un eleetrieul line joint tester, u hol- |o\\l seetionul huudle. u 'hollow trident l-hnped vmemher eurried upon one extremity of one of the .weetions of nid huudle. u eontuet hook eurried hv eueh of the prongs of luid trident l-lu|ped lnemher und insnlnted therefrom. u telephone reeeirer eonueeted to u puit' of -lid hooks through the hollow portions of suid handle und suid trident shnlped meudier. u ground eonneetion eonneetet to the renntiuing hook through the hollow portions ol snid lntudle und unid trident shnped melnher. und u switch mounted upon one of the et-tions ot lnid huudle uml udn ted to :illou' the eontinuity of -nid groluu to be mude or lu'oken ut will, for the purpose herein deerihod.

Signed h v me ut lilot Grove, Coupet' eounty uml Stute ol' Missouri. in the preseuee of tu'o witnesses.

lll'l.\'ll Y ll.\lllll1"().\' SH'SUN Wit nessi-s:

i the pulpos@ here- I 

